Wiseco K2751 3.875" Bore 9:1 Compression Ratio Reverse Dome Forged Piston Kit Fits: All Harley-Davidson Twin Cam 88 engines 1999-2006 with 4-3/8 inch stroke crank, Twin Cam 96 engines 2007-2013, Twin Cam 103 engines 2010-2013 103 cubic inch (1691 cubic capacity) big bore kit includes 9:1 compression ratio reverse dome pistons, rings, circlips, chrome piston pins Cylinder boring required, compatible with Screamin' Eagle cylinder heads (starting in 2011) Dedicated forgings are used for superior strength to weight ratio utilizing aerospace alloy with a dome designed for improved flame travel and detailed skirt shape and profiles for stability and smooth operation in the cylinder bore Utilizes the new ArmorGlide skirt coating, the ultimate in toughness, lubrication, and bond technology working together to minimize friction, maximize horsepower, providing improved wear resistance